Development of miniaturized piezoelectric actuators for optical applications realized using LIGA technology

To combine the advantages of the LIGA technology and piezoelectric materials, first prototypes of movable elastic LIGA structures have been realized on piezoelectric substrates. The structures consist of a flexible beam fixed to the piezoelectric substrate at its two ends in order to amplify the d/sub 31/-contraction of the piezoelectric substrate. By using this flexible LIGA beam as a magnification mechanism, the small displacements of the piezoelectric substrate are amplified by more than a factor of 20, offering various possibilities of applications, especially in micro-optics. In this paper, first the fabrication process and the performance of these new prototypes of LIGA piezoelectric actuators are described in detail, demonstrating the feasibility of the new concept combining the LIGA technique and piezoelectric substrates. Subsequently, LIGA-piezoelectric actuators developed for micro-optical applications are presented. These new optical actuators are also based on an elastic beam but slightly modified in order to modulate light propagating in optical fibers. They find promising applications as micro-optical attenuators or choppers whose performance is demonstrated.